42 



PROCEEDINGS OF THE NATIONAL MUSEUM 



Genus CARSIOFTYCHUS Simpson 



CARSIOPTYCHUS HAMAXITUS.^^ new species 



Type. — Left maxillary portion, U.S.N.M. No. 16197, with M^ and 



Horizon and locality. — ^^Vagonroad Paleocene, Dragon Canyon, 

 Emery County, Utah. 



Specific characters. — Teeth smaller than in Carsioptychus coarcta- 

 tus. Premolars slightly smaller with respect to molars than in C. 

 coarctatus and upper teeth relatively a little narrower transversely 

 than in the Puerco form. Lower premolars with slightly better 

 developed anterior stylid. 



Description. — Several specimens, including upper and lower teeth, 

 from the Wagonroad level represent a small species of Carsioptychus. 

 Though the teeth are small as compared to those in Carsioptychus 

 coarctatus, the form is slightly more progressive toward Periptychus 

 than is the Puerco species, but not so advanced as Periptychus gil- 

 morei from the Dragon. The premolars are relatively smaller than in 

 C. coarctatus and the upper molars, No. 16197 (fig. 22, &), and pre- 

 molars, No. 16198 (fig. 22, «), are relatively narrower transversely. 

 Moreover, the lower premolars show a slightly more advanced stage in 

 the development of an anterior stylid. The lower molars (fig. 22, c) 

 appear to be developed much as in C. coarctatus.^ and as in that species 

 show no evidence of the seventh cuspule, near the center of the tooth, 

 characterizing Periptychus cannidens, but seen only on Ms of P. 

 gilmorei. 



TaklA 8. — Measurements (in millimeters) of upper andS loicer teeth of 

 Carsioptychus hamaxitus 



1 Approximate. 



' The transverse diameter of the upper teeth is taken from the c-xternal cingulum to the base of the ename 

 lingually and at right angles to the direction of the tooth row. 



22 a/xo{iros, carriage road or wagon road, from the name of the horizon in which it was found 

 and the name of the ridge, at the lower end of which the locality occurs. 



